The number of illegal migrants crossing into the European Union (EU) in the West Balkan region has dropped by 90 per cent since Macedonia strengthened its border with Greece, EU border agency Frontex has said.

In March 4,930 people crossed the Greek-Macedonian border illegally, 10 per cent of the figure for the same month last year, according to Macedonian news agency Independent.

Despite the success of the Macedonian controls, however, the number of migrants entering Europe through Italy is growing as summer nears and conditions become more favourable to crossing the Mediterranean.

The Greek-Macedonian border has become a major flashpoint in recent weeks, especially around the town of Idomeni, with trapped migrants trying to break through the fence, often with the help of open borders activists.

Greek Prime Minister Alexis Tsipras claimed Macedonia had “shamed” Europe by closing its border and then deploying tear gas against migrants who tried to break through, but Macedonian President Gjorge Ivanov hit back, accusing Greece of failing to stop incursions onto its soil.

Last week, hundreds of migrants tried to storm the fence and bring it down, but were held back after Macedonian police used rubber bullets, tear gas and stun grenades. A leaflet had been circulating in the 11,000-strong Idomeni camp telling inhabitants to rise up and overwhelm the Macedonia guards.

Around 500 migrants attacked the fence, hurling stones at patrol cars and border police across the border, but a tip off led to Macedonia deploying more officers than usual.

Greek media blamed hard left ‘no borders’ activists for creating the detailed leaflets, leading to concerns Western radicals may be encouraging migrants to take dangerous risks to cross European borders. In March, thousands of migrants found themselves in detention while three drowned in a river after a similar attempted crossing.